The Senate Majority PAC — a Democratic super PAC that landed a $2.5 million contribution from former New York City Mayor Michael Bloomberg in July of last year — currently is at the top of the heap among outside groups spending on political campaigns, according to data compiled by Sunlight’s Real-Time FEC tracker.

The super PAC already has spent more than $7.8 million dollars in the 2014 cycle, most of which went towards attack ads in close Senate races like Louisiana and North Carolina. The group has been hammering Republican candidates over ties to the Koch brothers, the campaign finance juggernauts behind a network of politically active nonprofits, which are not compelled to disclose their donors to the Federal Election Commission.

You can follow the running totals for outside spending groups here. Our independent expenditure page is one of many features Sunlight is offering to help you follow the money now that primary season is upon us. Sunlight’s Reporting Group will be following along with you, keeping tabs on the super PACs, party committees and political nonprofits trying to influence votes in the upcoming elections.

Here are some other findings from our campaign finance and ad trackers:

Ending Spending enters New Hampshire race, Scott Brown soon to follow

While a clerical error meant that Scott Brown has yet to officially enter the New Hampshire Senate race, TD Ameritrade founder Joe Ricketts‘ Ending Spending is wasting no time wading in to the race — touting the former two-time Senate candidate’s longtime stance against Obamacare and the 20,000 New Hampshirites that “have had their coverage cancelled under Obamacare.” Here’s the ad, which is airing just in time for Brown’s official announcement, scheduled for Thursday:

Meanwhile, Democratic opposition research group American Bridge 21st Century has sprung to the aid of the incumbent Brown wants to oust, Democrat Jeanne Shaheen. Brown is one of a series of GOP candidates that American Bridge labels “an opponent of equal pay” in a series of Internet ads timed for Tuesday, which not-so-coincidentally happens to be Equal Pay Day. The ad criticizes Brown for his opposition to the Paycheck Fairness Act.

So far, the race has not attracted an outpouring of money from national political groups, but from the looks of Shaheen’s campaign filings, Brown will have a challenge matching the Democrat’s hard money fundraising efforts. The incumbent started the year with nearly $3.4 million on hand. Even so, Shaheen isn’t leaving anything to chance. Geographical barriers not withstanding, Shaheen and Georgia Senate candidate Michelle Nunn established a joint fundraising committee, the Georgia New Hampshire Victory Fund, so that the Democratic duo may fundraise together.

Advertisers’ nirvana

Nunn, like her ally in New Hampshire, is also being targeted by the Ending Spending Action Fund, which spent over a quarter million dollars on media production and placement in early April. Nunn, the former CEO of the Points of Light Foundation and daughter of longtime Peach State senator Sam Nunn, will face the winner of a crowded GOP field.

Sunlight’s Political Ad Sleuth shows that the Atlanta airwaves have been saturated with political advertising in recent weeks. Local  TV stations’ political ad files show that Nunn, Ending Spending, as well as Republican candidates David Perdue and John Kingston have all bought air time — mostly targeting the 35+ demographic with ad slots during the local news.

The home stretch in Florida 19

In Florida’s 19th Congressional District, where a special April 22 GOP primary may effectively decide who replaces former Republican congressman Trey Radel,state senator Lizbeth Benacquisto isn’t backing down.

At least that’s what she tells us in her new TV ad (see below), responding to attack ads from the Values are Vital super PAC, which has spent just over $950,000 backing Dr. Paige Kreegel in the primary. The committee has faced some allegations of improper coordination with the Kreegel campaign.

Benacquisto has also drawn outside support; the Liberty and Leadership Fund spent $370,00 on attack ads aimed at Curt Clawson, the businessman and former college hoops star.

Gay marriage group’s ads feature high profile Republican

Freedom to Marry — a nonprofit group dedicated to legalizing gay marriage — kicked off a national campaign Tuesday with an ad featuring a testimonial from retired Sen. Alan Simpson, R-Wyo. In the clip, the former Republican deputy Senate leader makes the case for gay marriage on libertarian grounds, citing the Western values he was raised with in his hometown of Cody, Wyo., “I’m a Republican and the party’s basic core is government out of your life and the right to be left alone. Whether you’re gay or lesbian or straight, if you love someone and you want to marry them, marry them.”

Political ad filings from Ad Sleuth show that the group has also purchased time slots in Denver and Washington, D.C. The ads launch the same week as hearings are set to begin in a lawsuit before the 10th U.S. Circuit Court of Appeals challenging Utah’s same-sex marriage ban.